Engineers at Lincoln Laboratory led by MIT and Whirlwind alumnus Kenneth Olsen built “Transistorized eXperimental computer zero” or “Tix Oh,” the TX-0 computer, an experimental high-speed digital computer for testing transistor circuitry and very large magnetic core memory. Transistors were expensive ($30–$80 each compared with $3–$10 per tube), and TX-0 used 3,600 total. The Lincoln team soon learned the new technology was very reliable. This console features a built-in cathode-ray tube display that reveals the influence of the SAGE radar console systems. One especially notable feature was the light-pen that enabled operators to interact with programs while they are running. The very large (64K RAM!) memory, speed, and reliability of the TX-0 made it one of the most advanced computers in the world when fully operational in 1957. However, Lincoln engineers were busy building an even bigger and faster computer, the TX-2. Lincoln soon “loaned” the TX-0 to MIT’s Research Laboratory of Electronics, where it was used for years—and was still operational in the 1980s—to make pioneering contributions that included speech and handwriting recognition.